LiquidPiston Awarded Phase II Army Contract to Advance Hybrid Electrification for Unmanned Aerial Vehicles (UAVs)

Company’s jet-fueled Hybrid Electric X-Engine (HEXE) Propulsion System to Address Army’s VTOL Goals for FTUAS and beyond

BLOOMFIELD, Conn., Sept. 13, 2022 (GLOBE NEWSWIRE) -- LiquidPiston, Inc., the leading innovator of efficient engine technology and hybrid power systems, today announced a $1.7 million Phase II award from the U.S Army to continue the development of the company’s Hybrid Electric X-EngineTM (HEXE) propulsion system. The Phase II award is a result of successful completion of a Phase I xTechSearch Small Business Innovation Research (SBIR) award previously announced. LiquidPiston’s HEXE propulsion system, prototyped and demonstrated at the end of Phase 1, will deliver fuel-efficient power as well as advanced take-off and inflight capabilities to meet the Army’s Future Tactical Unmanned Aircraft System (FTUAS) Vertical Take-Off and Landing (VTOL) goals, including compatibility with military-grade heavy fuels such as JP8. The hybrid system changes the concept of operation, allowing quiet, electric-only cruise in addition to electric-assist sprint and climb modes.

“Reliable and efficient sources of power and energy for intelligence, surveillance and reconnaissance (ISR), weapons systems, forward operating bases, and other solutions are critical to protecting the warfighter, enhancing warfighting capability, improving fuel efficiency, and reducing logistical burden and operational costs,” said Alec Shkolnik, Founder and CEO of LiquidPiston. “Unfortunately, the domestic industrial base for aerospace-grade, highly efficient engine systems is struggling. Today’s diesel engines are too big and heavy to be used in UAVs, and many UAV engines are sourced internationally. LiquidPiston is primed to address these challenges for the DoD and for broader mobility applications with greater power to weight requirements.”

LiquidPiston’s X-EngineTM utilizes the breakthrough thermodynamic concepts of the company’s patented High-Efficiency Hybrid CycleTM (HEHC) in a totally re-imagined compact rotary engine architecture that overcomes the limitations of the traditional Wankel rotary engine. The result is a purpose-designed power source for a hybrid-electric propulsion platform where portability, efficiency, low maintenance and jet fuel compatibility all work to overcome current range and payload shortcomings. In particular, the X-Engine propulsion system can toggle power between all-electric, engine-only, or a combination of both - all on demand - while being able to restart the engine in-air on jet fuel. The system recharges batteries in flight, so that the batteries can be sized to provide power vertical takeoff and landing as well as up to 30 minutes of quiet (electric) cruise. The HEXE VTOL system allows the Army to launch and land in small areas, and set up and stow quickly. Additionally, by combining electric and engine power on the main propeller shaft, the system achieves increased flight velocity (electric-assist “sprint”) and climb rates as well as optimized hybrid-electric range.

LiquidPiston CEO Alec Shkolnik will present on the Hybrid Electric Rotary X-Engine at the Turbine Engine Technology Symposium 2022 (TETS) in Dayton, OH as part of the Innovative Propulsion Concepts Session at 10:30 a.m. on Thursday, September 15th.

“One of the Army’s major areas of focus for modernization is Future Vertical Lift (FVL)” said Zeke Topolosky, Strategic Partnerships Office, U.S. Army Combat Capabilities Development Command Army Research Laboratory. “Over the past few years, Army xTech judging panels have repeatedly recognized LiquidPiston’s technological developments in holding great promise for supporting critical Army requirements for FVL modernization. We are pleased to see their efforts advance with this Army Phase II SBIR program.”

LiquidPiston has over 70 patents related to thermodynamics and advanced engine design that will enable a new family of engines and generators that are lightweight, compact, highly efficient and portable. This Phase II contract builds on more than 10 years of R&D with DARPA, the Army, and industry leaders to improve the maturity of the X-Engine technology.

About LiquidPiston: LiquidPiston, Inc., a Bloomfield, Conn-based technology startup, is leading the power systems industry’s development of efficient, fossil- or renewable fuel-capable combustion engines that are compact - delivering 1.5 HP/lb - and scalable - from one horsepower (HP) to over 1,000. The company’s patented High Efficiency Hybrid CycleTM (HEHC), together with breakthrough innovations in engine architecture, support next-generation fuel-energy conversion solutions for hybrid power systems, including for UAS, mobile power generation, and APU applications.

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Media Contact
Kaitlyn Gartling
CSG for LiquidPiston 

A photo accompanying this announcement is available at

LiquidPiston X-Engine